Brain Tumors: Removing a Brain Tumor
Guest: Dr. Sunil Patel - Neurosurgery
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I’m Dr. Linda Austin. I’m interviewing Dr. Sunil Patel who is Chief of Neurosurgery here at MUSC. Dr. Patel, we’ve talked some about the diagnostic workup of tumors. Let’s imagine that the news is good, that this appears to be a very slow-growing tumor, what are some examples of slow-growing or benign tumors of the brain?
Dr. Sunil Patel: There is a variety of types of tumors we consider benign in the brain. The more common ones people hear about are tumors called meningiomas. Really, they’re not truly brain tumors. Meningiomas are actually tumors of the meninges. The meninges are the lining that covers the brain. But, nonetheless, they’re inside the skull and so we consider them as “brain tumors.” Other tumors that are benign are pituitary tumors. There are also nerve tumors. There are a lot of nerves that leave the brain to various functions in the face. Acoustic neuromas are tumors of the vestibular nerve. Schwannomas are considered benign tumors. There are also some pineal tumors, cystic tumors of various portions of the brain, more commonly the temporal lobe. So there is a variety of different types of benign tumors.
Dr. Linda Austin: Are there statistics on, roughly, if you take patients who present with symptoms of a brain tumor, what percent will be so-called benign versus malignant?
Dr. Sunil Patel: Yeah. If you look at all primary brain tumors, unfortunately the more common thing is a diffuse malignant brain tumor. The benign ones usually don’t present to us. Because benign tumors are benign, for example, meningiomas, some statistics have shown that maybe even one in five women will have a tiny meningioma in their brain and not know it. So, even though the benign tumors may, in reality, be more common, they never present for treatment, and likely don’t need to be treated. They grow so slowly. So, what needs treatment ends up being more commonly the malignant ones. It depends on how you ask the question. What occurs more commonly are probably benign tumors. But what really need treatment are the malignant ones.
Dr. Linda Austin: Well, let’s take that group that do come for treatment, let’s say on the basis of headache or double vision or something like that, after you’ve evaluated, you’ve come to the conclusion that it’s probably a benign tumor. I know one of your areas of interest is a minimally invasive approach to these tumors. First, what do you mean by minimally invasive?
Dr. Sunil Patel: I think it’s not as much a fad, but it’s from the growing interest in all surgery, in all surgical fields, but even more so in neurosurgery, that once we have perfected the art of surgically excising a tumor and saving a patient’s life and curing them, then, as a surgeon, one needs to perfect the technique to reduce the harm to the patient in the process of removing such a tumor.
From the beginning of surgery, the constant technique improvement to doing smaller incisions, smaller holes, less “exploration”, and you can imagine you want to do as little exploration in an organ like the brain as possible. It’s a very functional organ, every inch of it is important. So, minimally invasive surgery has caught on big time in neurosurgery, and that’s an area of interest for me. My training was in skull base surgery which involves removing tumors in the underside of the brain where very large benign tumors grow. This is the area of the brain that has a lot of important nerves and arteries going through it.
During my training, over 15, 20 years ago, we would do these very large elaborate operations on the patient’s skull to get to these tumors and safely remove them without hurting the patient. But, in the end, the patient would have these huge incisions and large scars and a lot of morbidity associated with it. Well, more and more, as technology has come into the operating room, now we’re using image-guided systems, endoscopy, learning better the anatomy of the tumors as well as the anatomy of the skull base. We’re able to anatomically do only what’s absolutely necessary in terms of incision size, getting to these tumors through the shortest path, because we now have endoscopic techniques. We have image guidance.
What we do, for example, one good example is pituitary tumors. First of all, the pituitary tumors are tumors of the pituitary gland and they usually cause hormonal trouble. In the old days, we would take these tumors out by doing a craniotomy, opening the skull, or sometimes we would go under the lip, make an incision through the nose, take the septum out, go into the sinus, and with the microscope, take them out. And we did a good job. These patients were cured, but they had a lot of morbidity associated with pain over their teeth, that sort of stuff.
Well, for the past 10 years now, we’ve been using an endoscope where we don’t make any cuts or incision on the patient. We just go up the nostril, right into the sinus at the back, hardly making a cut, getting right into the gland which is sitting right on the other side of the sinus and removing the tumor. The operations last usually less than an hour and the patients usually go home the next day. So, we’ve really changed the way patients go through this surgery. It’s almost as an outpatient-type procedure now. A tumor inside your head being removed as an outpatient would be the ultimate future for these patients.
So, minimally invasive surgery involves a better understanding of the anatomy and a better understanding of the pathology, and bringing newer technology into the operating room so that we can hurt the patient the least, shorten their recovery, and still achieve the same goal of curing them.
Dr. Linda Austin: You’ve used the term image-guided. Can you explain a little bit more about that? I know there’s an elegance to how that’s done and I’d love to hear you talk about that.
Dr. Sunil Patel: Image guidance is a wonderful thing. It’s found its place in a lot of different areas in neurosurgery, including the operating room where we use it for minimally invasive surgery. Basically, this is what image guidance is: In the old days, we do an MRI scan, look at the picture on the MRI and see where the tumor is, and then go into the operating room and have the MRI stuck up on the board, and sort of guess, a reasonably good guess, about where the incision should be and where we should open the skull and where we might find this, based on just some anatomic landmarks. Now what we have, with image-guidance, is a way of localizing and object in space.
And the best way for me to explain this is to discuss how the GPS system works. You may be aware of the GPS system that we all use in our cars. How is it that we’re able to tell, when sitting in our car, using our GPS system, where the car is in relationship to its surroundings? It’s because 24 satellites are floating up there around the earth and tracking our car. And it takes a minimum of three satellites to track exactly where you are on the landscape. So, optics are used to localize your car and, through mathematical calculations, tell exactly where the car is on a map. And that’s exactly what you see on your GPS screen.
We use something similar in the operating room now. We have three cameras, sometimes two, that track instruments. So, the camera, first, knows exactly where the patient’s head is in the room. These cameras are sitting inside the operating room and they know exactly where the head is. Those cameras are hooked to a computer, so now the computer knows where in the room the head is. The computer is also fed the MRI images of this patient. So, the computer now has information on where the head is. It has information on where in the head the tumor is, based on the MRI scan. And, if you take a probe and show it to the camera, now the computer can show you where the probe is in relationship to the head and in relationship to the tumor. So, the computer is doing all the work for you, and it’s precise, to the nearest millimeter.
We started using image-guided surgery at MUSC 10 years ago and we’ve kept up with that technology. With the most recent technology, within less than a millimeter, we can apply electrodes, localize tumors. We’re never lost in the operating room. For the first time, neurosurgeons have the greatest confidence going into the head, not getting lost, and knowing exactly where things are. Sometimes, in the old days, we would leave tumor behind, no chance for that now. The computer would say, well, there’s something right around that corner, or right behind that blood vessel, look there, because the computer knows where the tumor is, knows where your probe is, knows where the patient’s head is. It’s like grandma’s always watching us. We have our own satellite, so to speak, in our own operating room, watching exactly what we do. So, that’s image guidance.
The other things, you asked me about image guidance, so let me tell you where else image guidance has really helped neurosurgery. That is in radiation, in the way we radiate tumors. If you can imagine the best people understand about radiation is radiation beams go from one part of your body through your body, through the cancer, and out the other end. But wouldn’t it be great if you could take an even tinier beam and just focus it and zap it right on a little tumor? And where else do we need that more than the brain? Every cell in the brain is important, so it would be nice to just target a little beam of radiation right on the tumor.
Well, the grandma system I talked to you about, the image guidance, can do that. So, we have image-guided radiation now. And some people understand that to be _____ (10:04) system, Gamma-knife. And the whole area of radiating small things in the brain is called stereotactically-directed radiosurgery (SRS). So, the area of SRS really uses image guidance a lot. And now, we can create one to two millimeter-size lesions in the brain without touching the patient’s head.
Dr. Linda Austin: That is so exciting.
Dr. Sunil Patel: Very exciting.
Dr. Linda Austin: Dr. Patel, thanks so much for describing that. It’s really incredible work.
Dr. Sunil Patel: Thank you.
Dr. Linda Austin: Thanks.
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